An April 22 hearing held by the Senate Subcommittee on Oceans, Atmosphere, Fisheries, and Coast Guard examined the economic and environmental impacts of ocean acidification. The hearing coincided with both the 40th anniversary of Earth Day and the release of a prepublication summary of a new National Research Council report, Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean.

The global ocean has absorbed about one-third of total anthropogenic carbon dioxide emissions since the Industrial Revolution, causing the pH of the water to decrease at an unprecedented rate and producing a suite of changes in oceanic chemistry known as ocean acidification. In response to growing concerns about the potential impacts of ocean acidification on marine ecosystems, Congress requested the National Research Council (NRC) to conduct a study on ocean acidification to help federal agencies develop their understanding of and ability to address the issue. (The NRC is the operational arm of the U.S. National Academies, including the National Academy of Sciences.)

“The chemistry of the ocean is changing at an unprecedented rate and magnitude due to anthropogenic carbon dioxide emissions; the rate of change exceeds any known to have occurred for at least the past hundreds of thousands of years. Unless anthropogenic CO2 emissions are substantially curbed, or atmospheric CO2 is controlled by some other means, the average pH of the ocean will continue to fall. Ocean acidification has demonstrated impacts on many marine organisms. While the ultimate consequences are still unknown, there is a risk of ecosystem changes that threaten coral reefs, fisheries, protected species, and other natural resources of value to society.”

Subcommittee Chair Maria Cantwell (D-WA) and Ranking Member Olympia Snowe (R-ME) both spoke to concerns about the potential environmental and socioeconomic impacts of ocean acidification. Senator Snowe said that “if current trends in ocean acidification continue, by the end of this century vast areas of the sea could very well become inhospitable to many species which form the foundation of the marine food web,” and that we “simply cannot leave the future of our oceans and their valuable resources to chance.”

Link to archived webcast of the hearing and witness written testimony here.

The following witnesses testified:

Actress Sigourney Weaver;
Dr. James Barry, Senior Scientist at the Monterey Bay Aquarium Research Institute;
Donny Waters, Commercial Fisherman and former President of the Gulf of Mexico Reef Fish Shareholders Alliance;
Tom Ingram, Executive Director of the Diving Equipment and Marketing Association; and
Dr. John Everett, President of Ocean Associates, Inc.

Sigourney Weaver testified as an advocate for public awareness of the largely unknown problem of ocean acidification. “I am not here as a scientific or policy expert,” she said, “but as a concerned citizen.” Weaver narrated the National Resources Defense Council film Acid Test: The Global Challenge of Ocean Acidification, and has continued to lend her visibility to promoting public education on the issue.

Dr. Barry said that declining pH levels will affect organisms in different ways, as the capabilities for acclimation and adaptation and thresholds for extinction vary greatly between species. Ocean acidification may affect many physiological processes in marine organisms, including calcification, photosynthesis, nutrient acquisition, growth, reproduction, and survival, and may be especially detrimental to organisms that form calcium carbonate shells and skeletons, Barry said.

The NRC report notes: “acidifying seawater to various extents has been shown to affect the formation and dissolution of calcium carbonate shells and skeletons in a range of marine organisms including reef-building corals, commercially-important mollusks such as oysters and mussels, and many phytoplankton and zooplankton species that form the basis of marine food webs.”

Mr. Waters spoke to concerns that ocean acidification may damage fisheries and other marine food sources, posing a risk to the livelihoods that rely on them. He said that although fish are not dying yet, “I don’t want to turn my back on this.”

Congress also called for the establishment of a federal ocean acidification program in the Federal Ocean Acidification Research and Monitoring Act of 2009, and the NRC report provides recommendations for developing this program. The report summary concludes:

“Given that ocean acidification is an emerging field of research, the committee finds that the federal government has taken initial steps to respond to the nation’s long-term needs and that the national ocean acidification program currently in development is a positive move toward coordinating these efforts.”

The NRC report recommends that the program encompass the following priorities: